An Enthusiasm for Orchids Sex and Deception in Plant Evolution

The male thynnine wasp's extreme sexual enthusiasm is crucial to reproduction of hammer orchids in the wild. Hammer orchids have co-evolved to produce odors identical to those manufactured by female thynnine wasps. The male wasp's superb sensitivity to the scent of his female mate is the basisfor the hammer orchid's deceit--in effect, orchids exploit the male insect's highly adaptive sense of smell for their own propagation. While pollinating orchids is a waste of time, and thus a maladaptive activity for a wasp, his mistake comes about because he must react quickly whenever he senses apossible mate nearby. Alcock suggests that, "for insects, he who hesitates is lost, although perhaps it would be better to say that he who hesitates often loses a chance to pass on his genes." This book abounds with clever explanations for how these exceptionally complex flowers came to be shaped as they are. The reader can explore many aspects of orchid biology and history ranging from how some species avoid inbreeding, to the origins of orchids from an ancestor that belonged to theasparagus family. Examining each component of an orchid's flower, Alcock explains how the various parts work together to produce the plant's minute offspring. Each element of an orchid, as quirky as it may seem, is biologically significant, bearing the imprint of natural selection. Readers can sharein the delight that Darwin and all other orchid enthusiasts have felt in making sense of even the smallest of details of these most wonderful plants.

John Alcock is Regents Professor in the School of Life Sciences at Arizona State University.